What are the uses of welded steel pipes

Welded steel tube, also known as welded steel pipe, is basically a steel pipe made of steel plate or strip steel after crimping and welding. The production process of welded steel pipe is simple, the production efficiency is high, there are many varieties and specifications, and the equipment investment is small, but the general strength is lower than that of seamless pipe.

Since the 1930s, with the rapid development of continuous rolling production of high-quality strip steel and the advancement of welding and inspection technology. The quality of the weld seam is continuously improved, and the varieties and specifications of welded steel pipes are increasing day by day, and they have replaced seamless steel pipes in more and more fields. Welded steel pipes are divided into straight seam welded pipe (LSAW pipe) and spiral welded pipe (SSAW pipe) according to the form of weld seam.

1. Classification of welded pipes

Welded pipes are classified according to their uses: according to their uses, they are divided into general welded pipes, galvanized welded pipes, oxygen-blown welded pipes, wire casings, metric welded pipes, supporting pipes, deep well pump pipes, automotive pipes, transformer pipes, electric welding thin-walled pipes,Electric welded special-shaped pipes and spiral welded pipes.

2. Application range of welded pipe

Welded pipe products are widely used in boilers, automobiles, ships, building light-weight door and window steel, furniture, various agricultural machinery, scaffolding, wire threading pipes, high-rise shelves, containers, etc. Can meet customer requirements, special specification welded pipe can be processed according to user requirements.

3. The use of welded pipe

There are many types of welded pipes. Due to the differences in welding methods and steel pipe sizes, different welded pipes have different characteristics and can be used in different fields.

General welded pipe: General welded pipe is used to convey low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be manufactured from other mild steels that are easy to weld. Steel pipes are subject to water pressure, bending, flattening and other tests, and have certain requirements for surface quality. Usually, the delivery length is 4-10m, and it is often required to be delivered in fixed length (or double length). The specification of the welded pipe is represented by the nominal diameter (mm or inch). The nominal diameter is different from the actual one. The welded pipe has two types of ordinary steel pipe and thickened steel pipe according to the specified wall thickness. The steel pipe is divided into two types: threaded and unthreaded according to the pipe end form.

Galvanized steel pipe: In order to improve the corrosion resistance of steel pipes, general steel pipes (black pipes) are galvanized. There are two types of galvanized steel pipes: hot-dip galvanizing and electro-galvanizing. The hot-dip galvanizing layer is thicker and the cost of electro-galvanizing is low.

Oxygen welded pipe:Used as a pipe for oxygen blowing in steelmaking, generally small-diameter welded steel pipes, with eight types of specifications ranging from 3/8 inch to 2 inch. Made of 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.

Wire Sleeve:That is, ordinary carbon steel electric-welded steel pipes are used in concrete and various structural power distribution projects, and the commonly used nominal diameters are from 13-76mm. The wall of the wire casing is relatively thin, and it is mostly used after coating or galvanizing, and a cold bending test is required.

Metric welded pipe:Used seamless pipe specification, welded steel pipes expressed in mm of outer diameter * wall thickness. It is welded with hot or cold strips of ordinary carbon steel, high-quality carbon steel or ordinary low-alloy steel, or welded with hot spots and then cold drawn. Metric welded pipes are divided into ordinary energy and thin-walled pipes, which are generally used as structural parts, such as transmission shafts, or conveying fluids, and thin-walled pipes are used to produce furniture, lamps, etc., to ensure the strength and bending test of steel pipes.

Roller tube:Electric welded steel pipes for belt conveyor rollers are generally made of Q215, Q235A, B steel and 20 steel, with a diameter of 63.5-219.0mm. There are certain requirements for the bending degree of the pipe, the end surface should be perpendicular to the center line, and the ellipticity, and the water pressure and flattening tests are generally carried out.

Transformer tube:It is used to manufacture transformer cooling pipes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending, and hydraulic tests. Steel pipes are delivered in fixed length or multiple lengths, and there are certain requirements for the bending degree of steel pipes.

Shaped tube:Square tubes, rectangular tubes, hat-shaped tubes, hollow plastic steel doors and windows steel pipes welded by ordinary carbon-bonded structural steel and 16Mn steel strips are mainly used as agricultural machinery components, steel windows and doors, etc.

Welded thin-walled tube:It is mainly used to make furniture, toys, lamps, etc. In recent years, thin-walled tubes made of stainless steel strips have been widely used in high-end furniture, decoration, fences, etc.

Spiral welded pipe: It is made by rolling low-carbon carbon structural steel or low-alloy structural steel strip into a tube blank according to a certain helical angle (called forming angle), and then welding the pipe seam. It can produce large-diameter steel pipes from narrower strips. Spiral welded pipes are mainly used for oil and natural gas transmission pipelines, and their specifications are expressed by outer diameter * wall thickness. Spiral welded pipes are single-sided welded and double-sided welded. The welded pipes should ensure that the hydraulic test, the tensile strength of the weld and the cold bending performance must meet the regulations.

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